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    <title>Document</title>
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    <script>
        var foo;
        (function(){
            var foo = 2;
            console.log(foo);
        })();
        console.log(foo);

        console.log(0.8-0.2 ===0.6);

        function test(str){
            return str.split("").reverse().join('');
        }

        let a = 'helloword',
            b = test(a);
        console.log(b);

        return obj.split('').reverse().join('')

    </script>
    
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